excel-mcp-server has a Path Traversal issue

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.4 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H

EPSS

• CVE-2026-40576: 0.46% estimated exploitation activity in the next 30 days; percentile 40.30 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A path traversal vulnerability exists in `excel-mcp-server` versions up to and including `0.1.7`. When running in SSE or Streamable-HTTP transport mode (the documented way to use this server remotely), an unauthenticated attacker on the network can read, write, and overwrite arbitrary files on the host filesystem by supplying crafted `filepath` arguments to any of the 25 exposed MCP tool handlers. The server is intended to confine file operations to a directory set by the `EXCEL_FILES_PATH` environment variable. The function responsible for enforcing this boundary — `get_excel_path()` — fails to do so due to two independent flaws: it passes absolute paths through without any check, and it joins relative paths without resolving or validating the result. Combined with zero authentication on the default network-facing transport and a default bind address of `0.0.0.0` (all interfaces), this allows trivial remote exploitation.…

Published by the source

14 Apr 2026, 00:03 UTC

Last modified by the source

27 Oct 2026, 16:45 UTC

Source last checked

28 Oct 2026, 06:05 UTC

1. Revision 5 · amended · 28 Oct 2026

   Amended from osv record GHSA-j98m-w3xp-9f56

2. Revision 4 · amended · 27 Oct 2026

   Amended from ghsa record GHSA-j98m-w3xp-9f56

3. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-j98m-w3xp-9f56

4. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-j98m-w3xp-9f56

5. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-j98m-w3xp-9f56

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# Patch Next advisory brief: CVE-2026-40576

Advisory: excel-mcp-server has a Path Traversal issue
IDs: CVE-2026-40576, GHSA-j98m-w3xp-9f56
Record: https://patchnext.com/advisories/cve-2026-40576 (revision 5, source checked 28 Oct 2026, 06:05 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: excel-mcp-server 0.1.8. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI excel-mcp-server: affected < 0.1.8; fixed in 0.1.8

## Suggested inspection (read-only)
- `python -m pip show excel-mcp-server`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on excel-mcp-server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-j98m-w3xp-9f56 (GitHub-reviewed advisory GHSA-j98m-w3xp-9f56 lists affected ranges: PyPI excel-mcp-server >=0 <=0.1.7)
- Verified: https://osv.dev/vulnerability/GHSA-j98m-w3xp-9f56 (OSV record GHSA-j98m-w3xp-9f56 lists affected ranges: PyPI excel-mcp-server >=0 <0.1.8 (fixed))

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